What is SPF and how does it work?

What is SPF?

SPF is a record added to a domain's DNS Zone File that fights return-path e-mail address forgery and helps prevent spammers from “spoofing” your e-mail address. It is a way for you to identify what servers are allowed to send mail for your domain. And lastly, it is a way for receiving mail servers to verify if an email really came from the domain it is specifying.

What does SPF stand for?

SPF stands for Sender Policy Framework.

How does SPF work?

The actual functionality of SPF is too long and complicated to cover in a KB article. So in a nutshell, SPF is a way of allowing the domain owner to specify what servers on the internet can send mail for that domain. These servers can be your web site, web server, mail server, SMTP server, or another persons server that sends email on behalf of your domain. When an e-mail is checked against SPF, the mail will only go through if it passes the SPF check. This check involves getting your SPF record from DNS, checking the IP address of the sending mail server, and verifying it against your SPF record. Now please keep in mind that this is a very watered down of what really happens.


For more information about SPF records please go to http://spf.pobox.com

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